The invention relates in general to stamping machines and in particular to a new and useful bottom or female die provided with a cutting edge closed in itself, for stamping machines having a seat for a bottom die.
Such dies are usually manufactured on wire erosion machines, with the core being erroded by means of a wire. This is a complicated and thus relatively expensive operation having in addition the disadvantage that the inside surfaces of the die worked in this way are relatively rough. Other methods of making holes are also difficult, primarily if an angular or arcuate inside surface is provided. Since they are made of a brittle material, bottom dies have still another disadvantage, namely that they break at their corners upon overload.